This is true and I never suggested that NUME was intended to replace CWN. If you look at the videos on https://mikeellismusicinstruction.com/Nume/index.html you will see one of my students at age eight and nine playing the piano parts to two songs by the Beatles, having used the NUME method at that very young age to learn them. The "Martha My Dear" piece is pretty involved and he plays it all the way through with the recording.Tab for guitar is really for beginning students.
Also, on that page you can see the quote from Professional Music Instructor Dan Anderson who sent the following comment about NUME. "Your NUME notation system is so sensible it makes me feel guilty for putting kids through our convoluted traditional system." Notice, he said kids.

We learned to talk before we learned to read and write and if I can get a student to play music they love before learning CWN, it just might entice them to give CWN a try. I totally advocate learning CWN and I always told my students they should definitely learn to read notes the conventional way. It was just faster and more fun to be able to play before learning the complexities of CWN.
Thanks again, Fred.